The present invention is directed to a system and method for creating multiple lateral wells through a wall of a common well bore which enables lateral and longitudinal orientation of the system at multiple lateral and longitudinal positions in the common well bore and positive, selective reentry of each lateral well.
Several advantages are provided by drilling relatively high angle, deviated or lateral wells from a generally common well bore such as a) access to the regular oil and gas reserves without additional wells being drilled from the surface, b) avoiding unwanted formation fluids, c) penetration of natural vertical fractures, and d) improved production from various types of formations or oil and gas reserves. Additionally, reentry of one or more lateral wells is often required to perform completion work, additional drilling, or remedial and stimulation work. Thus, lateral wells have become commonplace from the standpoint of new drilling operations and reworking existing well bores, including remedial and stimulation work.
Ordinarily, lateral well completion and/or reentry requires expensive downhole wireline surveys to accurately position the diverter or whipstock which is used to direct the boring or completion tool through a wall of a generally vertical well bore into the adjacent formation. Without a survey, the lateral well formed may not be accurately recorded for purposes of reentry. For example, U.S. Pat. Nos. 4,304,299; 4,807,704; and 5,704,437 each describe a method and/or apparatus for producing lateral wells from a generally vertical common well bore using conventional techniques and tools. In each instance, one or more lateral wells may be produced at a different depth and location in the common well bore and reentered. Consequently, the whipstock must be repositioned at the new depth and location. Each time the whipstock is repositioned at a different depth and location, the change in depth and lateral orientation relative to a point of reference is recorded. In most applications using conventional threaded connections as thus described, the exact depth and location of each lateral well formed cannot be accurately or efficiently recreated using the same system and technique. As a result, a downhole directional survey is necessary to relocate the exact depth and location of each lateral well upon reentry.
Recognizing the disadvantages of the foregoing techniques, U.S. Pat. No. 2,839,270 and, more recently, U.S. Pat. No. 5,735,350 have attempted to address the need for a more accurate method and/or apparatus for producing, relocating and reentering lateral wells without the need for a directional survey. For example, U.S. Pat. No. 2,839,270 describes a technique for selectively forming a lateral well through a wall of a common well bore at a predetermined depth and lateral orientation by means of a supporting apparatus which includes apertures formed at predetermined locations in the supporting apparatus. The apertures determine the relative depth and lateral orientation of each lateral well and are prefabricated according to the particular common well bore in which the supporting apparatus is installed. The whipstock is then positioned using one or more specially designed latches which engage a correspondingly designed aperture for receipt of the respective latch.
Similarly, U.S. Pat. No. 5,735,350 describes a method and system for creating lateral wells at preselected positions in a common well bore by means of a diverter assembly having a plurality of locator keys specially designed to engage a corresponding nipple formed in the well bore casing having a unique profile. Although this technique may be employed in new and existing wells, it is expensive and, in some instances, inappropriate because the prefabricated keys and nipples are permanently and integrally formed according to the particular formation characteristics of the common well bore in which the system is installed.
Notwithstanding the conventional attempts at obtaining cost effective and efficient lateral well completion, there is a recognized need for new and improved methods and devices. In particular, there is a need for a cost effective and efficient system and technique for completion of lateral wells which is inexpensive to manufacture, easy to install and may be utilized on new and pre-existing wells. Moreover, there is a need for a technique and system for completion of lateral wells which may be used in a variety of new or preexisting well bores to create and reenter a plurality of different lateral wells without the need for expensive directional surveys or prefabricated equipment.
It is therefore, a primary object of the present invention to provide a system and method for creating lateral wells through a wall in a common well bore which may be used in new and preexisting well bores to vary the depth and lateral orientation of each lateral well in a cost-efficient and timely manner.
It is another object of the present invention to provide a system and method for creating lateral wells through a wall in a common well bore which may be reinstalled in a particular well bore in order to relocate each lateral well for selective reentry.
It is an advantage of the present invention to provide for the use of conventional and/or standardized equipment in the formation and reentry of multiple lateral wells.
In accordance with the foregoing objects and advantages, the present invention provides an improved system for creating multiple lateral wells through a wall of the common well bore extending from the earth""s surface or other point of drilling and completion operations. In accordance with a preferred embodiment, the system comprises an anchor, an orienting member, an extension member, a diverter, and a probe. The anchor includes a packer secured within the common well bore at a predetermined position. The anchor, or packer, also includes a longitudinal reference point and a lateral reference point. The orienting member includes a muleshoe and stinger assembly slidably engaged within the anchor for initial orientation of the system relative to the lateral reference point. The extension member has a first end releasably connected to the orienting member and a second end. The diverter includes a whipstock with an angled or arcuate face which is releasably connected to the second end of the extension member. The probe includes a boring tool which is releasably connected to the diverter for creating a lateral well when the face of the diverter directs the probe toward the wall of the common well bore upon release of the probe from the diverter. This embodiment of the system enables lateral orientation of the diverter at multiple positions relative to the lateral reference point, positioning the diverter at multiple longitudinal positions relative to the longitudinal reference point, and reentry of each of the respective lateral wells created. Each connection between the first end and second end of the extension member and the respective orienting member and diverter restricts rotational and translational movement of each respective connection upon makeup and maintains alignment between the first end and second end of the extension member and the respective orienting member and diverter in a single direction.
In another preferred embodiment wherein the extension member includes one or more segments for positioning the diverter at multiple longitudinal positions, each segment is releasably connected to another respective segment. Each connection between the segments restricts rotational and translational movement of the connection upon makeup. One connection between the plurality of segments enables alignment between the respectively connected segments in multiple directions while the remaining connections maintain alignment between the respective segments in a single direction. The connection enabling alignment in multiple directions is used to laterally orient the diverter in multiple lateral directions and the connection maintaining alignment in a single direction is used to accurately relocate each lateral well upon reentry. One of the plurality of segments closest to the diverter may include another anchor secured within the common well bore for stablizing the diverter.
In another preferred embodiment, the connection of the first end and second end of the extension member to the respective orienting member and diverter restricts rotational and translational movement of each respective connection upon makeup. One connection enables alignment between the extension member and the respective orienting member and diverter in multiple directions, while another connection maintains alignment between the extension member and the respective orienting member and diverter in a single direction. In this embodiment, the extension member may include one or more segments for positioning the diverter at multiple longitudinal positions. Each segment is releasably connected to another respective segment. Each connection between the segments restricts rotational and translational movement of the connection upon makeup and maintains alignment between the plurality of segments in a single direction. The connection enabling alignment in multiple directions is used to laterally orient the diverter in multiple lateral directions while the connection maintaining alignment in a single direction is used to accurately relocate each lateral well upon reentry.
In a preferred embodiment, the lateral reference point includes a key attached to the anchor. The orienting member includes a channel for receipt of the key whereby engagement of the key within the channel enables the initial orientation of the system. The orienting member includes a flange. The anchor includes a channel for receipt of the flange whereby engagement of the flange within the channel prevents rotational movement of the orienting member.
In another preferred embodiment, the present invention provides an improved method for creating multiple lateral wells through a wall of a common well bore using a system of releasably connected components comprising an orienting member, an extension member, a diverter, and a probe. The extension member has a first end releasably connected to the orienting member and a second end releasably connected to the diverter. The orienting member includes a muleshoe and stinger assembly slidably engaged within the anchor for initial orientation of the system relative to the lateral reference point. The diverter includes a whipstock with an angled arcuate face which is releasably connected to the probe. The probe includes a boring tool for creating a lateral well when the face of the diverter directs the probe toward the wall of the common well bore upon release of the probe from the diverter.
The method comprises the steps of a) securing an anchor within the common well bore at a predetermined position, b) lowering the system into the common well bore until the orienting member slidably engages the anchor for initial orientation of the system relative to the lateral reference point, c) releasing the probe from the diverter, and d) creating a lateral well through the wall of the common well bore using the probe. The step of releasing the probe from the diverter may be performed by compressing the system, whereby the probe is released from the diverter upon compression of the system. The step of creating the lateral well with the probe may further comprise one of the steps of milling through the wall of the common well bore and boring into an adjacent formation in the earth. Although creating the lateral well may be performed in a single run in some applications, in most applications the lateral well is created in two separate runs because two different probes are used to mill an opening or xe2x80x9cwindowxe2x80x9d in a casing lining the common well bore and drill through the formation. As a result, the probe used to mill must be removed at the surface and replaced with the probe used to drill, thus requiring two separate runs to complete a lateral well.
Reentry of the lateral well comprises the steps of replacing the probe with another probe, lowering the system into the common well bore until the orienting member slidably engages the anchor, and releasing the another probe from the diverter for reentry of the lateral well. The diverter is releasably connected to the another probe and is positioned at the first lateral position and the first longitudinal position.
In this embodiment, the anchor includes a packer secured within the common well bore at a predetermined position. The anchor, or packer, also includes a longitudinal reference point and a lateral reference point. The diverter is positioned at a first lateral position which is aligned with the first lateral reference point and a first longitudinal position located a predetermined distance from the first longitudinal reference point. The orienting member includes a muleshoe and stinger assembly slidably engaged within the anchor for initial orientation of the system relative to the lateral reference point. The diverter includes a whipstock with an angled or arcuate face. The probe includes a boring tool which is releasably connected to the diverter for creating a lateral well when the face of the diverter directs the probe toward the wall of the common well bore upon release of the probe from the diverter. This embodiment of a method for using the system thus described, enables lateral orientation of the diverter at multiple positions relative to the lateral reference point, positioning the diverter at multiple longitudinal positions relative to the longitudinal reference point, and selective reentry of each of the respective lateral wells created.
In a preferred embodiment, the method further comprises the step of performing a directional survey for determining the predetermined position of the anchor. Once the anchor is lowered into the common well bore, a directional survey is performed and the anchor is hydraulically or mechanically secured at a predetermined position.
In another preferred embodiment wherein the extension member includes one or more segments for positioning the diverter in multiple longitudinal positions, each segment is releasably connected to another respective segment. Each connection between the segments restricts rotational and translational movement of the connection upon makeup. One of the segments closest to the diverter may include another anchor for stablizing the diverter, the method further comprising the step of securing the other anchor within the common well bore below the diverter.
In yet another embodiment of the present invention, the method further comprises the steps of a) removing the system from the common well bore upon completion of the lateral well, b) adjusting a length of the extension member, c) positioning the diverter at a second lateral position relative to the lateral reference point, d) lowering the system into the common well bore until the orienting member slidably engages the anchor, e) releasing the probe from the diverter, and f) creating another lateral well through the wall of the common well bore using the probe. The step of removing the system upon completion of the lateral well comprises removing the probe from the common well bore with a drill string connected to the probe and retrieving the orienting member, extension member and diverter from the common well bore with a fishing tool. In this embodiment, the extension member includes a first end and a second end. The first end and second end of the extension member is releasably connected to the respective orienting member and diverter for restricting rotational and translational movement upon makeup. One connection enables alignment between the extension member and the respective orienting member and diverter in multiple directions, while another connection maintains alignment between the extension member and the respective orienting member and diverter in a single direction. The step of adjusting a length of the extension member may include a) removing the extension member and replacing it with another extension member having a different length than the existing extension member, b) simply connecting another extension member to the existing extension member; or c) where the extension member includes a plurality of releasably connected segments, removing one of the segments.
Reentry of the other lateral well comprises the steps of replacing the probe with another probe, lowering the system into the common well bore until the orienting member slidably engages the anchor, and releasing the another probe from the diverter for reentry of the another lateral well. The diverter is releasably connected to the another probe and is positioned at the second lateral position and the second longitudinal position. The diverter is positioned at a second longitudinal position relative to the longitudinal reference point. Thus, the diverter may be positioned to create another lateral well having coordinates corresponding with the second lateral position and second longitudinal position.
In another preferred embodiment, the lateral reference point includes a key attached to the anchor. The orienting member includes a channel for receipt of the key whereby engagement of the key within the channel enables the initial orientation of the system. The orienting member includes a flange. The anchor includes a channel for receipt of the flange whereby engagement of the flange within the channel prevents rotational movement of the orienting member. The diverter includes a whipstock having an angled face.
Although the terms longitudinal and lateral are used herein for convenience, those skilled in the art will recognize that the system and method of the present invention may be employed with respect to wells which extend in directions other than generally vertical or horizontal.
The foregoing has outlined rather broadly the objects and advantages of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional objects and advantages of the invention will be described below which form the subject the subject of the claims of the invention. Those skilled in the art should appreciate that they may readily use the conception and specific embodiment disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.